Point-of-care testing: the views of the working group of the Dutch Association of Clinical Chemistry.

There is clearly a demand for near-patient laboratory testing. Modern technological developments support its implementation, but these are not the only preconditions that need to be satisfied in order to successfully introduce decentralized testing. In part 2 of this paper we give a definition of decentralized testing. Part 3 presents the advantages and disadvantages. This list is a summary taken from the suggested literature. Part 4 examines the formal position of the clinical chemist. Of major importance to the situation in the Netherlands are the Care Institutions Quality Act and the Individual Health Care Professions Act. Part 5 discusses professional standards. Part 6 outlines practical considerations which might support the implementation of decentralized testing. The clinical chemist should play an active role in drawing up a discussion paper for his own hospital.

Automated Particle Analysis of Populations of Silver Halide Microcrystals by Electron Probe Microanalysis under Cryogenic Conditions.

An automated particle analysis routine is implemented on an electron microprobe for analyzing the chemical composition and projective area of populations of individual silver halide microcrystals. An LN2 cryostage is used to prevent material degradation due to reaction with the impinging electron beam. The background in the EDX spectra is lowered by depositing the microcrystals on a carbon-coated copper grid, mounted in a transmission holder. The ILα/AgLα net X-ray intensity ratio, obtained from a spectrum-fitting algorithm, is used to determine the crystal composition by means of a standard-based calibration curve. The uncertainty on the concentration measurement of individual microcrystals is calculated using the uncertainties on the net X-ray counts and the uncertainties on the calibration curve. The area measurement is optimized by introducing a gray value histogram correction on each individual measurement. Overlapping microcrystals are scrapped from the analysis by defining a maximum shape factor, against which the shape factor of the microcrystal is tested. To minimize problems with drift of the cryostage, spectrum acquisition is carried out immediately after a single microcrystal has been located, based on the backscattered electron image. Several applications are discussed.

Cimetidine-induced liver injury. Report of three cases.

Cimetidine-induced liver injury has only very rarely been reported. Three patients are described who developed signs of hepatic damage after the institution of cimetidine therapy. Transient signs of acute liver failure were noticed in one patient. Histologically, a cytotoxic type of injury with centrilobular confluent and bridging portal-central necrosis, accompanied by a mixed mono- and polymorphonuclear infiltrate with signs of cholangiolitis in the portal tracts was observed in two patients, whereas a hepatocanalicular type of cholestatic hepatitis was noticed in another patient. It is proposed that the mechanism of cimetidine-induced liver injury may vary in different patients: it may be due either to a 'metabolic idiosyncrasy' because of the production of hitherto unknown toxic metabolites or to a hypersensitivity reaction.